title: Does percutaneous nephrolithotomy in children cause significant renal scarring?
abstract: OBJECTIVE
  To determine the frequency of renal parenchymal damage following percutaneous nephrolithotomy (PCNL) in children.
  
  
  METHODS
  Fifty-six children undergoing PCNL in 60 renal units between January 2000 and December 2004 were included in this prospective study, and were subjected to postoperative technetium-99m dimercaptosuccinic acid ((99m)Tc-DMSA). Using a standard questionnaire, demographics, number, size and location of stones, procedure details, outcome as indicated by clearance with PCNL alone or additional procedures, and follow up were documented. Presence of focal renal damage and its association with the PCNL tract were examined.
  
  
  RESULTS
  Out of 60 renal units, cortical defects on (99m)Tc-DMSA scan were seen in 10 renal units (17%). In three of these kidneys, the site of focal defect corresponded to the access site for tract formation during PCNL. Two additional kidneys had scarring at multiple sites, one of which corresponded to the access site during PCNL. In the remaining five kidneys no association between focal renal damage and nephrostomy tract site could be ascertained. No association was seen between renal damage and the size of nephroscope used during PCNL.
  
  
  CONCLUSIONS
  There exists a risk of focal damage to renal parenchyma from the formation of the nephrostomy tract. In our series, focal damage was seen in 5% of patients; this may be an overestimate since preoperative (99m)Tc-DMSA scans were not available for our patients. Meticulous technique is important combined with a smaller nephroscope to minimize renal damage. Long-term follow up of such children is required to assess how many are left with permanent renal scars.
authors.affiliation: Division of Urology, The Kidney Centre Postgraduate Training Institute, 197 Rafiqui Shaheed Road, Karachi 75530, Pakistan.
authors.forename: Lubna
authors.initials: L
authors.lastname: Samad
authors.forename: Samia
authors.initials: S
authors.lastname: Qureshi
authors.forename: Zafar
authors.initials: Z
authors.lastname: Zaidi